Personally I will be judging RFOM 2, and KZ2 against this game. So this game is the benchmark for me.
Left 4 dead I will probably just compare to TF2.
You could call it a benchmark for quality, polish, graphics, multiplayer, controls, it likely does it all well. You could even use it to measure how the standards have changed for a AAA game between Late 2006 and now.
Tease.